Invisible mending for glass collectors, not fraudsters

You may have noticed that several of the pieces of glassware we have
offered for sale – as part of the detailed description – include notes
about any damage which may be present, any restoration which has been
carried out, and a note to the effect that it may be possible to
restore them to a near flawless condition.

This is a service
which we can undertake on your behalf working with trusted associates
who have perfected a method by which damaged glassware can be returned
to its original splendour. This is done using a restorative process
which avoids the potentially damaging procedures of grinding and
polishing to recondition chipped or flaked areas; as you can imagine, to
evenly re-grind the foot of a glass which has a quarter inch chip on
its edge requires the removal of that same measurement around its full
circumference, thus irrevocably altering the original proportions of the
piece which cannot possible retain its original balance and “feel”.

Reducing the diameter of the foot also means that its original concave
profile also has to be recreated – albeit across a smaller diameter;
this is achieved by further grinding to the underside of the foot, which
visibly reduces the thickness of the glass. This may be sometimes be
detected as one may observe score-marks – like spokes – which radiate
out from the stem on the underside of the foot. Sometimes artificial
wear and tear will then be added to the new “wear line” around the
circumference of the foot in an attempt to replicate the condition of a
piece which has been slid across table tops and bars, cleaned, polished,
balanced on stone mantles and unsympathetically curated by sundry
disinterested custodians or inebriated alehouse habitués over centuries
of use.

Rather than using these essentially destructive
techniques, we prefer to endorse a procedure – painstaking and highly
skilled in its own right – which uses a specially formulated epoxy resin
to effect the repairs by replacing damaged areas. These resins are not
simply “off the shelf” solutions, but are chosen from a wide range of
different grades which are paired with the original piece to provide the
closest possible match in appearance, shade and finish. They can also
be tinted using additives that provide the most exact match to the
target piece – be it the subtle grey shades of “clear” flint crystal, or
the more strident hues of coloured glassware (blues, greens, reds – any
of the popular antique casts…)

This matching process crucially
also includes an analysis of the refractive index of the piece. In
simple terms, this ensures that when light passes through both the
original glass and the resin insert, it is refracted at the same angle
and will, therefore, present what appears to be an entirely uniform
surface to the casual observer (if you want to get all technical and
swan about in a lab coat, clipboard in hand and looking terribly well
informed, the propagation of light through the two constituent parts
will be as near to identical as is possible, based on the determination
and calibration of analogous phase velocities in both substrates – so

A drawback of using these resins is that – in their
uncured state – they are very fluid, but need to be presented against
the intact part of the piece being repaired in such a way that as little
work on the cured inset as possible is required to avoid any further
imperfections being inadvertently imparted. In order to do this, a
silicone mould is taken from another part of the original which most
closely matches the form of the area to be repaired, in to which the
resin is introduced layer by layer until the full extent of the void
within the mould is filled.

The resin insert is then left – in
position – to cure for 48 hours at a carefully controlled temperature;
the curing process has the additional benefit of bonding the insert to
the original so there is no additional adhesive required; you need only
reflect on childhood repairs to Subbuteo figures or crockery – hastily
reassembled before parents were aware of the breakage – to know what a
give-away the presence of inexpertly applied glues can be; there is no
scope for such incrimination with a bonded insert !

Once in
place, the genuinely artistic aspect of the repair comes to the fore
with the polishing of the insert to replicate the surface of the
once-again complete item. This has the effect of both matching the
patina of the infill to the appearance of the original glass, and
allowing the conservator to replicate any existing striations on the
sound part of the piece. This polishing is done by the use of
increasingly fine glass papers and then varying grades of silicone
carbide polishing cloth, before a final burnish with a metal polish rub
is used to impart the required lustre.

It should be noted that
inserts created with these processes can be fairly readily detected
under very close scrutiny, but the piece will certainly look
sufficiently complete for display purposes. It is not the intention to
make the repairs entirely invisible, as this would inevitably lead to
the possibility for repaired items to be sold as undamaged and complete,
with the additional value inherent to any object in such purportedly
pristine condition. They can also be easily revealed by exposing the
restored piece to ultra-violet light, at which point the insert will be
made immediately obvious. This resin-based restoration is a service for
the owner who wishes to enhance an object that would otherwise be sadly
diminished by damage, in the full knowledge that such restoration has
been carried out, rather than offering the potential for obfuscation.
This is sadly not always the case for other procedures which claim to
deliver a repaired item intended be indistinguishable from an entirely
undamaged equivalent – that is a service not to the owner, but only to a
potential seller – and a gross disservice to any unwary collectors !

Both approaches to restoration have their merits depending upon the
nature of the piece requiring restoration. Chips to lustres if a
suitable replacement pendant or droplet cannot be found are better being
ground and polished when the chips are small. We prefer chips on the
bowl of wine glasses to be filled, not ground, and small chips on the
feet of glasses to be polished where the loss is minimal.

going on our website, all glasses are carefully checked for any
restoration, and it is always noted in our description of the glass. If
we state that there has been no restoration, that is a representation on
which you are entitled to rely. Where we consider restorative work may
be carried out with advantage, we will also note that.

Filled and
colour tinted restoration is universally accepted in the world of the
porcelain collector. We want the same to be true for the world of the
glass collector. It is inevitable that some glasses will have suffered
damage and restoration over their many years of service, but it is our
firm belief that the proper course is to make its existence clearly
known to our clients and that this should form a basic practice standard
within the antique trade.

(errr – and yes, it’s The Mending Song by the mice on Bagpuss – bonus points for anyone who spotted that)

an example of a repaired glass as listed on our site